Self-luminous device



Feb. 27, 1934. KELLY 1,948,718

SELF LUMINOUS DEVICE Filed March 29, 1932 INVENTOR a? wv am' ATTOR NEYSPatented Feb. 27, 1934 UNITED STATES PATENT OFFICE SELF-LUMINOUS DEVICEApplication March 29, 1932. Serial No. 601,757

1 Claim.

This invention relates to self-luminous devices, and with particularityto radium luminous markers for pendants or the like.

An object of the invention is to provide a selfluminous terminal for achain, cord or other similar object.

Another object is to provide a pull chain or cord with a self-luminousterminal marker of improved shape and construction.

A feature of the invention resides in a draw or pull chain, cord orsimilar article having a self-luminous terminal or marker, inconjunction with a novel form of light transparent housing for saidterminal.

A further feature of the invention resides in a terminal for a lampchain, cord or similar article which is designed so as to facilitate itslocation in the dark.

Other features and advantages not specifically enumerated will beapparent after a consideration of the following detail descriptions andthe appended claim.

While the invention will be described hereinafter as applied to a chainsuch as ordinarily used on electric lamps or the like, it will beunderstood that the invention is not limited thereto, but is capable ofapplication in any situation where a luminous terminal is required.

Accordingly in the drawing,

Fig. 1 represents a draw or pull chain having a self-luminous terminalaccording to the invention;

Fig. 1 represents a slight modification of the structure of Fig. 1;

Fig. 2 represents a modified form of the terminal of Fig. 1;

Figs. 3 and 4 represent still further modifications of the luminousterminal; and

Fig. 5 shows a still further modification of the invention.

Referring to Fig. 1, the numeral 1 represents any conventional type ofchain or cord such as is ordinarily employed on electric lamps forswitching the current on and off. It will be understood however that theinvention is not limited to the particular type of chain disclosed. Thechain as shown comprises a series of ball-like links 2 which terminateat the upper end in a coupling member 3 having an opening 4 adapted tofit over a chain similar to the chain 2. The chain 1 terminates at itslower end in an enlarged member 5, preferably of ball-like constructionalthough the invention is not limited in this respect to any particularshape for the member 5. However, it is found that when the member 5 ismade spherical that the greatest efficiency for self-luminous purposesis achieved. Furthermore, the member 5 may be the ordinary ball terminalof an electric light chain, or if desired it may take the form of aseparate body or spherical member attached in any convenient manner tothe lower end of the chain 1. The member 5 is provided with a coating 6of self-luminous material, preferably radium luminescent paint or thelike.

It has been found that this radium luminescent material has its greatestefiiciency as a self-iuminous coating when it is not covered by anylight absorption covering. Consequently, it is pre ferred to apply theradium luminescent coating to the member 5 so that the said coating isexposed, without any superposed layers of protective coating, althoughif desired a very thin protective coating of a transparent varnish maybe employed. In order to protect the coating 6, and at the same timeprovide a terminal which can be very readily grasped, there is provideda hollow housing 7 of glass or other transparent material such ascelluloid or the like. While Fig. 1 shows the member 7 bell shaped, itwill be understood that the invention is not limited in this respect toany particular shape, but is capable of various modifications some ofwhich are illustrated in Figs. 2, 3 and 4. The member 7 is provided atits I upper end with a small opening 8 to receive the chain 1. Ifdesired, reliance may be placed upon the member 5 to support the weightof the member 7. On the other hand, if desired the member 7 may besupported by the chain 1 proper, in any convenient manner, as bydeforming a pair of the chain links 2 between which the member 7 is tobe supported. Furthermore, if desired the member 7 may be loosely passedover the chain 1 so as to facilitate assembly, or if desired the member'7 may be cemented or otherwise rigidly fastened to the chain 1. Thehousing member 7 is preferably made of as thin glass as is consistentwith the requisite strength necessary during the use of the device, andany suitable design such as a series of gold bands or rings 9 may beprovided on the lower end of the said housing member 7 to enhance theappearance of the device.

From the foregoing it will be seen that because of the shape of themember 7, it presents a very artistic appearance to the chain and at thesame time provides the necessary surface extent to facilitate graspingof the device in a darkened room. Furthermore, the member 7 acts toprotect the radium luminescent coating on the member 5 withoutmaterially reducing the efliciency of the light that is emitted from thesaid member, thus the device is capable of being used without actualcontact with the coating 5 and with a minimum of light absorption in theprotecting housing. Instead of making the member '7 bell shaped it maybe of any other suitable shape such as a disc having downwardlyconverging edges or a hemispherical member such as illustrated in Fig.2. If the member 10 of Fig. 2 is of rather shallow construction then itmay be made of metal or other non-transparent material since itsshallowness enables the coated part or marker 5 to be visible through arelatively wide angle. However, it is preferred to make the member 10out of glass, celluloid or other light transparent material.

Fig. 3 shows a further modification wherein the bell shaped member 7 isattached to the chain in a reverse manner, that is with the mouth of thebell facing upwardly. In this case it may be necessary to provide anadditional ball or link 11 to prevent the member '7 pulling downwardly01f the chain.

Fig. 4 shows a still further modification wherein the enclosing terminalis in the form of a ball or sphere 12 substantially completely enclosingthe luminous marker 5. In this case of course the member 12 ispreferably provided with an opening 13 sufficiently large to permit aproper assembly and a washer or other suitable member 1 1 may beattached to the member 12 to prevent the said member from sliding offthe chain or if desired, the opening 13 may be closed in any othermanner for this purpose.

Fig. 5 shows a still further modification of the invention wherein thechain or cord 1 terminates at its lower end in a metal bell shapedmember 15 instead of a ball shaped member such as shown in Figs. 1 to 4inclusive. The member 15 has its outer surface provided with a coating16 of selfluminous material, such for example as a radium luminouscompound or a compound containing mesothorium. Surrounding the member 15is an enclosing housing 1'7 also preferably bell shaped and preferablyof glass, celluloid, or other transparent material. The upper end of thehousing 17 is provided with a perforation of sufficiently large diameterto pass over the ball links 2, but too small to pass over the terminal15. In order to prevent the housing 17 from sliding along the chain, anadditional large ball member 18 may be attached to the chain above thehousing 17. Instead of applying the coating 16 over the entire surfaceof the member 15, the said coating may be applied in discreet spotsaround the periphery of the said member 16. This of course also appliesto the coating on the member 5 of Figs. 1 to 4 inclusive. That is to saythis coating may be applied in either spots, bands or any other designthat is found suitable. Preferably, although not necessarily, the member15 of Fig. 5 conforms in shape to the housing 17.

It will be understood, of course, that in all of the foregoingmodifications the members 7, 10 and 12 may be perforated or even madeout of foraminous material to enable the light from the 100 coating 6 tobe emitted directly therethrough.

Various modifications and changes may be made herein without departingfrom the spirit and scope of the invention.

What is claimed is:

In combination a ball chain terminating in a bell shaped terminalmember, a coating of radium luminous material on said terminal member, atransparent glass bell supported directly by said terminal memberwhereby said coating is visible through said glass bell, said terminalmember substantially conforming in shape to the inner face of said glassbell.

JOSEPH A. KELLY.

